Should I sell my employee shares and move the cash into ETF’s?

I’ve just left my banking job where I had accumulated $45k in employee shares.

As part of leaving I had to exercise them which I have now done.

So my question is should I just sell them and move the cash into an ETF?

I’m in the highest tax bracket so assuming a 45% tax hit (is this payable at tax time next year?) leaving only ~$25k or so remaining.

Assuming the tax is due next FY should I move the whole $45k into ETF’s and use cash from my offset to pay the tax bill?

Or is there any tax benefit of holding them for 12 months?

I’m not confident in the company outlook over the next 12 months so I’m not expecting them to grow much from where there are if at all.

TIA